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Non-Contiguous I/O Support for Object-Based Storage

Dennis Dalessandro, Ananth Devulapalli, Pete Wyckoff
2008 Parallel Processing  
The access patterns performed by disk-intensive applications vary widely, from simple contiguous reads or writes through an entire file to completely unpredictable random access. Often, applications will be able to access multiple disconnected sections of a file in a single operation. Application programming interfaces such as POSIX and MPI encourage the use of non-contiguous access with calls that process I/O vectors. Under the level of the programming interface, most storage protocols do not
more » ... mplement I/O vector operations (also known as scatter/gather). These protocols, including NFSv3 and block-based SCSI devices, must instead issue multiple independent operations to complete the single I/O vector operation specified by the application, at a cost of a much slower overall transfer time. Scatter/gather I/O is critical to the performance of many parallel applications, hence protocols designed for this area do tend to support I/O vectors. Parallel Virtual File System (PVFS) in particular does so; however, a recent specification for object-based storage devices (OSD) does not. Using a software implementation of an OSD as storage devices in a Parallel Virtual File System (PVFS) framework, we show the advantages of providing direct support for non-contiguous data transfers. We also implement the feature in OSDs in a way that is both efficient for performance and appropriate for inclusion in future specification documents.
doi:10.1109/icpp-w.2008.23 dblp:conf/icppw/DalessandroDW08 fatcat:fytn5ahwejdqfjdfs32vmhawsq

Tapping into the fountain of CPUs

Yaron Weinsberg, Danny Dolev, Tal Anker, Muli Ben-Yehuda, Pete Wyckoff
2008 SIGPLAN notices  
The constant race for faster and more powerful CPUs is drawing to a close. No longer is it feasible to significantly increase the speed of the CPU without paying a crushing penalty in power consumption and production costs. Instead of increasing single thread performance, the industry is turning to multiple CPU threads or cores (such as SMT and CMP) and heterogeneous CPU architectures (such as the Cell Broadband Engine). While this is a step in the right direction, in every modern PC there is a
more » ... wealth of untapped compute resources. The NIC has a CPU; the disk controller is programmable; some high-end graphics adapters are already more powerful than host CPUs. Some of these CPUs can perform some functions more efficiently than the host CPUs. Our operating systems and programming abstractions should be expanded to let applications tap into these computational resources and make the best use of them. Therefore, we propose the HYDRA framework, which lets application developers use the combined power of every compute resource in a coherent way. HYDRA is a programming model and a runtime support layer which enables utilization of host processors as well as various programmable peripheral devices' processors. We present the framework and its application for a demonstrative use-case, as well as provide a thorough evaluation of its capabilities. Using HYDRA we were able to cut down the development cost of a system that uses multiple heterogenous compute resources significantly.
doi:10.1145/1353536.1346304 fatcat:tfba7lhmffajzgpyneiyetaqmm

EMP

Piyush Shivam, Pete Wyckoff, Dhabaleswar Panda
2001 Proceedings of the 2001 ACM/IEEE conference on Supercomputing (CDROM) - Supercomputing '01  
Modern interconnects like Myrinet and Gigabit Ethernet offer Gb/s speeds which has put the onus of reducing the communication latency on messaging software. This has led to the development of OS bypass protocols which removed the kernel from the critical path and hence reduced the endto-end latency. With the advent of programmable NICs, many aspects of protocol processing can be offloaded from user space to the NIC leaving the host processor to dedicate more cycles to the application. Many
more » ... offload messaging systems exist for Myrinet; however, nothing similar exits for Gigabit Ethernet. In this paper we propose Ethernet Message Passing (EMP), a completely new zero-copy, OS-bypass messaging layer for Gigabit Ethernet on Alteon NICs where the entire protocol processing is done at the NIC. This messaging system delivers very good performance (latency of 23 us, and throughput of 880 Mb/s). To the best of our knowledge, this is the first NIC-level implementation of a zero-copy message passing layer for Gigabit Ethernet.
doi:10.1145/582034.582091 dblp:conf/sc/ShivamWP01 fatcat:teqapyhl3rcnrh6fzz37q6ctkm

Hive

Ashish Thusoo, Joydeep Sen Sarma, Namit Jain, Zheng Shao, Prasad Chakka, Suresh Anthony, Hao Liu, Pete Wyckoff, Raghotham Murthy
2009 Proceedings of the VLDB Endowment  
doi:10.14778/1687553.1687609 fatcat:igl5reripfcfpghowmzqix5xta

Tapping into the fountain of CPUs

Yaron Weinsberg, Danny Dolev, Tal Anker, Muli Ben-Yehuda, Pete Wyckoff
2008 SIGARCH Computer Architecture News  
The constant race for faster and more powerful CPUs is drawing to a close. No longer is it feasible to significantly increase the speed of the CPU without paying a crushing penalty in power consumption and production costs. Instead of increasing single thread performance, the industry is turning to multiple CPU threads or cores (such as SMT and CMP) and heterogeneous CPU architectures (such as the Cell Broadband Engine). While this is a step in the right direction, in every modern PC there is a
more » ... wealth of untapped compute resources. The NIC has a CPU; the disk controller is programmable; some high-end graphics adapters are already more powerful than host CPUs. Some of these CPUs can perform some functions more efficiently than the host CPUs. Our operating systems and programming abstractions should be expanded to let applications tap into these computational resources and make the best use of them. Therefore, we propose the HYDRA framework, which lets application developers use the combined power of every compute resource in a coherent way. HYDRA is a programming model and a runtime support layer which enables utilization of host processors as well as various programmable peripheral devices' processors. We present the framework and its application for a demonstrative use-case, as well as provide a thorough evaluation of its capabilities. Using HYDRA we were able to cut down the development cost of a system that uses multiple heterogenous compute resources significantly.
doi:10.1145/1353534.1346304 fatcat:2pdsxowd6nevzmajjbdq2vi34a

Tapping into the fountain of CPUs

Yaron Weinsberg, Danny Dolev, Tal Anker, Muli Ben-Yehuda, Pete Wyckoff
2008 ACM SIGOPS Operating Systems Review  
The constant race for faster and more powerful CPUs is drawing to a close. No longer is it feasible to significantly increase the speed of the CPU without paying a crushing penalty in power consumption and production costs. Instead of increasing single thread performance, the industry is turning to multiple CPU threads or cores (such as SMT and CMP) and heterogeneous CPU architectures (such as the Cell Broadband Engine). While this is a step in the right direction, in every modern PC there is a
more » ... wealth of untapped compute resources. The NIC has a CPU; the disk controller is programmable; some high-end graphics adapters are already more powerful than host CPUs. Some of these CPUs can perform some functions more efficiently than the host CPUs. Our operating systems and programming abstractions should be expanded to let applications tap into these computational resources and make the best use of them. Therefore, we propose the HYDRA framework, which lets application developers use the combined power of every compute resource in a coherent way. HYDRA is a programming model and a runtime support layer which enables utilization of host processors as well as various programmable peripheral devices' processors. We present the framework and its application for a demonstrative use-case, as well as provide a thorough evaluation of its capabilities. Using HYDRA we were able to cut down the development cost of a system that uses multiple heterogenous compute resources significantly.
doi:10.1145/1353535.1346304 fatcat:g7v3gh7s55gwpltpdqxuc43lum

Revisiting the metadata architecture of parallel file systems

Nawab Ali, Ananth Devulapalli, Dennis Dalessandro, Pete Wyckoff, P. Sadayappan
2008 2008 3rd Petascale Data Storage Workshop  
doi:10.1109/pdsw.2008.4811892 fatcat:dp7jxp35gbcfzcill75ezdvca4

Memory Management Strategies for Data Serving with RDMA

Dennis Dalessandro, Pete Wyckoff
2007 15th Annual IEEE Symposium on High-Performance Interconnects (HOTI 2007)  
Using remote direct memory access (RDMA) to ship data is becoming a very popular technique in network architectures. As these networks are adopted by the broader computing market, new challenges arise in transitioning existing code to use RDMA APIs. One particular class of applications that map poorly to RDMA are those that act as servers of file data. In order to access file data and send it over the network, an application must copy it to user-space buffers, and the operating system must
more » ... ter those buffers with the network adapter. Ordinary sockets-based networks can achieve higher performance by using the "sendfile" mechanism to avoid copying file data into user-space buffers. In this work we revisit time-honored approaches to sending file data, but adapted to RDMA networks. In particular, both pipelining and sendfile can be used, albeit with modifications to handle memory registration issues. However, memory registration is not wellintegrated in current operating systems, leading to difficulties in adapting the sendfile mechanism. These two techniques make it feasible to create RDMA-based applications that serve file data and still maintain a high level of performance.
doi:10.1109/hoti.2007.5 dblp:conf/hoti/DalessandroW07 fatcat:bqi4z77zzfdepg3km66fffzxp4

File Creation Strategies in a Distributed Metadata File System

Ananth Devulapalli, Pete Wyckoff
2007 2007 IEEE International Parallel and Distributed Processing Symposium  
As computing breaches petascale limits both in processor performance and storage capacity, the only way that current and future gains in performance can be achieved is by increasing the parallelism of the system. Gains in storage performance remain low due to the use of traditional distributed file systems such as NFS, where although multiple clients can access files at the same time, only one node can serve files to the clients. New file systems that distribute load across multiple data
more » ... are being developed; however, most implementations concentrate all the metadata load at a single server still. Distributing metadata load is important to accommodate growing numbers of more powerful clients. Scaling metadata performance is more complex than scaling raw I/O performance, and with distributed metadata the complexity increases further. In this paper we present strategies for file creation in distributed metadata file systems. Using the PVFS distributed file system as our testbed, we present designs that are able to reduce the message complexity of the create operation and increase performance. Compared to the basecase create protocol implemented in PVFS, our design delivers near constant operation latency as the system scales, does not degenerate under high contention situations, and increases throughput linearly as the number of metadata servers increase. The design schemes are applicable to any distributed file system implementation.
doi:10.1109/ipdps.2007.370295 dblp:conf/ipps/DevulapalliW07 fatcat:znt4pbdv3bd5zcswlhthrmkyuy

Design and Implementation of MPICH2 over InfiniBand with RDMA Support [article]

Jiuxing Liu, Weihang Jiang, Pete Wyckoff, Dhabaleswar K. Panda, David Ashton, Darius Buntinas, William Gropp, Brian Toonen
2003 arXiv   pre-print
For several years, MPI has been the de facto standard for writing parallel applications. One of the most popular MPI implementations is MPICH. Its successor, MPICH2, features a completely new design that provides more performance and flexibility. To ensure portability, it has a hierarchical structure based on which porting can be done at different levels. In this paper, we present our experiences designing and implementing MPICH2 over InfiniBand. Because of its high performance and open
more » ... , InfiniBand is gaining popularity in the area of high-performance computing. Our study focuses on optimizing the performance of MPI-1 functions in MPICH2. One of our objectives is to exploit Remote Direct Memory Access (RDMA) in Infiniband to achieve high performance. We have based our design on the RDMA Channel interface provided by MPICH2, which encapsulates architecture-dependent communication functionalities into a very small set of functions. Starting with a basic design, we apply different optimizations and also propose a zero-copy-based design. We characterize the impact of our optimizations and designs using microbenchmarks. We have also performed an application-level evaluation using the NAS Parallel Benchmarks. Our optimized MPICH2 implementation achieves 7.6 μs latency and 857 MB/s bandwidth, which are close to the raw performance of the underlying InfiniBand layer. Our study shows that the RDMA Channel interface in MPICH2 provides a simple, yet powerful, abstraction that enables implementations with high performance by exploiting RDMA operations in InfiniBand. To the best of our knowledge, this is the first high-performance design and implementation of MPICH2 on InfiniBand using RDMA support.
arXiv:cs/0310059v1 fatcat:tkaemmkasjbcteqgxl7veggily

Memory Management Strategies for Data Serving with RDMA

Dennis Dalessandro, Pete Wyckoff
2007 15th Annual IEEE Symposium on High-Performance Interconnects (HOTI 2007)  
Using remote direct memory access (RDMA) to ship data is becoming a very popular technique in network architectures. As these networks are adopted by the broader computing market, new challenges arise in transitioning existing code to use RDMA APIs. One particular class of applications that map poorly to RDMA are those that act as servers of file data. In order to access file data and send it over the network, an application must copy it to user-space buffers, and the operating system must
more » ... ter those buffers with the network adapter. Ordinary sockets-based networks can achieve higher performance by using the "sendfile" mechanism to avoid copying file data into user-space buffers. In this work we revisit time-honored approaches to sending file data, but adapted to RDMA networks. In particular, both pipelining and sendfile can be used, albeit with modifications to handle memory registration issues. However, memory registration is not wellintegrated in current operating systems, leading to difficulties in adapting the sendfile mechanism. These two techniques make it feasible to create RDMA-based applications that serve file data and still maintain a high level of performance.
doi:10.1109/hoti.2007.4296817 fatcat:jxi2k2blivddtpnboygmsl2tsa

Accelerating Distributed Computing Applications Using a Network Offloading Framework

Yaron Weinsberg, Danny Dolev, Pete Wyckoff, Tal Anker
2007 2007 IEEE International Parallel and Distributed Processing Symposium  
During the last two decades, a considerable amount of academic research has been conducted in the field of distributed computing. Typically, distributed applications require frequent network communication, which becomes a dominate factor in the overall runtime overhead. The recent proliferation of programmable peripheral devices for computer systems may be utilized in order to improve the performance of such applications. Offloading applicationspecific network functions to peripheral devices
more » ... improve performance and reduce host CPU utilization. Due to the peculiarities of each particular device and the difficulty of programming an outboard CPU, the need for an abstracted offloading framework is apparent. This paper proposes a novel offloading framework, called HYDRA that enables utilization of such devices. The framework enables an application developer to design the offloading aspects of the application by specifying an "offloading layout", which is enforced by the runtime during application deployment. The performance of a variety of distributed algorithms can be significantly improved by utilizing such a framework. We demonstrate this claim by evaluating several offloaded applications: a distributed total message ordering algorithm and a packet generator.
doi:10.1109/ipdps.2007.370319 dblp:conf/ipps/WeinsbergDWA07 fatcat:iuldebnz7rb6vad3bjhg4s4kii

Performance of RDMA-capable storage protocols on wide-area network

Weikuan Yu, Nageswara S.V. Rao, Pete Wyckoff, Jeffrey S. Vetter
2008 2008 3rd Petascale Data Storage Workshop  
Because of its high throughput, low CPU utilization, and direct data placement, RDMA (Remote Direct Memory Access) has been adopted for transport in a number of storage protocols, such as NFS and iSCSI. In this presentation, we provide a performance evaluation of RDMA-based NFS and iSCSI on Wide-Area Network (WAN). We show that these protocols, though benefit from RDMA on Local Area Network (LAN) and on WAN of short distance, are faced with a number of challenges to achieve good performance on
more » ... ong distance WAN. This is because of (a) the low performance of RDMA reads on WAN, (b) the small 4KB chunks used in NFS over RDMA, and (c) the lack of RDMA capability in handling discontiguous data. Our experimental results document the performance behavior of these RDMA-based storage protocols on WAN.
doi:10.1109/pdsw.2008.4811885 fatcat:yrox3ilofjcc5iqk3e5rlnblca

High performance RDMA-based MPI implementation over InfiniBand

Jiuxing Liu, Jiesheng Wu, Sushmitha P. Kini, Pete Wyckoff, Dhabaleswar K. Panda
2003 Proceedings of the 17th annual international conference on Supercomputing - ICS '03  
Pete Wyckoff from Ohio Supercomputer Center for valuable discussions. We thank Sushmitha Kini, Darius Buntinas, Weikuan Yu and Balasubraman Chandrasekaran for their help with the experiments.  ... 
doi:10.1145/782814.782855 dblp:conf/ics/LiuWKWP03 fatcat:7swpfrsn6jafvgqxyn2vr7kdae

Attribute Storage Design for Object-based Storage Devices

Ananth Devulapalli, Dennis Dalessandro, Pete Wyckoff, Nawab Ali
2007 24th IEEE Conference on Mass Storage Systems and Technologies (MSST 2007)  
As storage systems grow larger and more complex, the traditional block-based design of current disks can no longer satisfy workloads that are increasingly metadata intensive. A new approach is offered by object-based storage devices (OSDs). By moving more of the responsibility of storage management onto each OSD, improvements in performance, scalability and manageability are possible. Since this technology is new, no physical object-based storage device is currently available. In this work we
more » ... scribe a software emulator for an object-based disk. We focus on the design of the attribute storage, which is used to hold metadata associated with particular data objects. Alternative designs are discussed, and performance results for an SQL implementation are presented. 24th IEEE Conference on Mass Storage Systems and Technologies (MSST 2007) 0-7695-3025-7/07 $25.00
doi:10.1109/msst.2007.4367983 fatcat:uzkvdrdyh5ajze435hbj46ioge
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